Tool shield



L A F F A F P F E D L E m s L o O T 2 Sheets-Sheet 1 Filed. Nov. 12, 1954 INVENTORES:

I ATTORNEY L A F F A F P F E Feb. 23, 1960 D L E m S L o o T 2 Sheets-Sheet 2 Filed Nov. 12, 1954 ATTORNEY TOOL SHIELD This invention relates to a fastener driver and more particularly to an explosive operated stud driving tool.

In the use of explosive operated tools of the type A disclosed in US. Patent Nos. 1,365,869 and 1,365,870 for driving studs or pins into structural materials it is often desirable to install the studs into rounded cylindrical objects such as columns, rods, poles, and pipe, for example. In such installations it is not only difficult to properly position the tool for projecting the fastener, but the operation of driving studs into these round structures creates an extremely hazardous situation. 'It will be appreciated that in installations of this type as compared to installations where stud driving occurs squarely into substantially planar surfaces, there is a greater tendency for the fastener to ricochet and endanger those in the vicinity of the operator and that ricocheting of such offangle fasteners is of greater concern than the flash and occasional flash swept particles which may accompany the driving operation. Heretofore available types of tools, including thosewith shields, pads or guards, have provided no improvement in this respect over the tool with an unguarded muzzle.

Therefore, one object of the invention is to provide an improvement in explosive operated fastener driving tools for enabling the setting of fasteners properly into cylindrical or other curvilinear surfaces of like nature.

Another object is the provision of a new self-aligning tool assuring on round surfaces controlled and safe operation of explosive actuated driving tools in all directions on such work surfaces.

Another object is the provision of a new and improved tool with a muzzle structure which substantially eliminates the likelihood of a fastener escaping into free flight as a result of inability of center the tool with round work surfaces properly.

A still further object is to provide on such tools a selfcentering and aligning safety shield for receiving spall particles and the blast from the muzzle thereby protecting not only the tool operator but also protecting other workmen in the vicinity from ricocheting missiles.

Other objects and advantages will be evident from the description and the accompanying drawing of preferred embodiments of-the invention in which:

Figure l is an elevational view partly in cross-section showing part of a driving tool in accordance with one embodiment of this invention;

Figure 2 is a fragmentary perspective view showing the muzzle end of the tool positioned against the work ready for driving operation;

Figure 3 is an elevational view partly in cross-section showing a second embodiment of the tool of the present invention; and

Figure 4 is .a plan view of the embodiment of Figure 3 taken on line IVIV of Figure 3.

In accordance with this invention the muzzle end of an explosive actuated stud driving tool is provided with a safety shield adapted to center itself on the surface of cylindrical parts and to substantially retain disrupted par- 2,925,600 r Pa e ed Fe 28, 1 0

2. ticles such as spall fragments and the like within the shield structure. The shield of muzzle guard pad of this invention comprises a box-like structure opened at one side at which it is presented to the work and having peripheral notches which enable the shield and the tool associated with it to be aligned properly with the work surface. Specifically, the side walls of the shield are notched in accordance with this invention. .A V-notch at any suitable angle in each of'a pair of opposing walls is contemplated which will accommodate the rounded surfaces usually encountered. The shield or muzzle guard may be provided with a notch having a fixed angle or a variable angle. When cylindrical objects of relatively large diameter constitute the work, the angle of the notch is preferablynear butsomewhatless than When cylindrical object of small diameter constitute the work the notch is at a more acute angle. Although for a given angle of notch a considerable range of-work diameters can be handled,,the range can be extended by providing a shield in accordance with'thisinvention having an adjustable V-notch. Furthermore, in accordance with a preferred form of the invention, it is contemplated Ice that thev open side of the shield structure adjacent the notches be provided with enclosures in the form of plates or the like the better to retain disrupted and ricochettin materials. 5 The embodiment of Figures 1 and 2 isillustrated-in connection with the muzzle portion of a tool of the type disclosed in the copending application of Kopf, Henning and Marsh, Seria1.No. 355,034, filed May '14, 1953 for explosively actuated tools.. A tool of this type comprises an outer barrel tube or housing 1, mounted for movement on barrel 2 so that thehousing may be pushed forward relative to the barrel 2 into operative relationship when the tool barrel muzzle is placed against the surface into which the stud is to be installed and the tool pressed firmly against such surface. This type of tool also includes a shield tube or sleeve 3 for mounting the shield and a barrel spring 4, which is a compression type of spring adapted to press against the inner flange 5 of shield tube 3 so as to urge the tube and shield forwardly. The barrel is threaded at the muzzle 10 and carries a thread'cap 9 which serves totransmit the thrust'of barrel spring 4 acting through'sleeve 3 to the barrel 2an'd also as an axial retainer for the shield or" muzzle guard structure. i I

In this embodiment as shown in Figures-1 and '2, the

self-centering safety shield structure takes the form of a receptacle consisting in general of a rear'safety plate 6, which is apertured at 20 to receive the tool barrel 2,,the

four side walls 11, 12, 1-3 and 14, two of which 'are notched, and the partial closure plates 17 and 18 at the extremities of the notches, disposed at an angle and spaced, leaving the area between the apex of the notches open. At the aperture 20 the safety shield. "is adapted to be attached at the muzzle of the barrel tool coaxially' in any suitable manner as by being fixed on shield tube 3 which is constrained axially to have limited movement between cap 9 and spring 4. Although the invention described in connection with this embodiment is adapted to be attached to this form of explosive driving tool, it is to be understood that the invention in its general concept is not limited to the structural details or'the arrangement of parts of a tool since the invention is adapted to be used with various forms of explosive;

operated tools or the like.

side walls which in turn are provided with partial front enclosures all of which with the plate define a hollow guard and alignment structure. Two of these side walls, 11' and 12, are V-notched to match at an angle the a ex of which is desginated in'Figure l as 8. It is to be noted thattheinner dihedral angle at apex 8 is advantageously somewhat more acute than the outer angle defined by the end guard plates 17 and 18. The interior portion of the box-like-shieldstructure of this embodiment-islined with ashield pad 7-of resilient material such as a'heat resistant synthetic rubber which may be molded into the steel-housing of the shield to extend over the plate 6 and also over portions of the side walls 1-1, 12; 13 and 14. n the exterior the shield structure may-be provided vwith pairs of guide linesor indicia marks 35 and 16 as shown in Figure 2 for the purpose-of enabling the tool operator to readily and more accurately-position the tool at-a desired location for insertion of a fastener. Although in -this embodiment the-safety shield plate (land the self-alignment-; shield structure is shown to have a rectangular form, other forms such as a circular form may also be employed. I

. The .plateLfi and side walls -11, 12, 13 and 14 maybe advantageouslyrformed integrally-from a -single sheet of metal; suchas steelof suitablethickness topic-vent penetnation by-deflected fragments. in thisevent,- the rear plate 6, which prevents rearward projection of flash-and fragments, .is providedwithmarginal extensions-making notchedside walls 11 and Hand unnotched side walls 13 and 14 all four of which together provide a protective flange portion to substantially prevent-excessive lateral deflection of'flash and particles trained in thefiash. Forward ejectionof missiles is substantially prevented by the spaced angle plates defining the outer portion or extremities of the dihedral angle formed by the notches. The rear plate 6 and the side walls form amenclosure about the muzzle of the tool together withthe angle plates except' for the apertured portion 20 adapted to permit passage, of the muzzle of the tool barrel and except for the opening at apex 8.

The notched side walls 11 and 12 are oppositely disposed about rear Plate 6 and carry V-shaped cut-outs disposedwith suitable accuracy in side walls Hand 12 in relationship with rear plate 6 and the tool barrel aperture 20 thereinso asto place the axis of the tool barrel perpendicular to the portion of the cylindrical surface into which thefastener is to be projected. Thus side walls 1 1 and 12 are of generally identical geometrical construction as far as the shape and the location of the V-notch in each is concerned. While his preferred that 4 either apex 8 or at the plates 17 and 18 are firmly in engagement with the cylindrical surface. This places the entire shield structure in proper alignment and centered position on the cylindrical surface of the work 19. Because of the structural relationship of the notched side walls 11 and 12, and theapertured rear plate 6, it will be evident to those skilled in the art that the barrel of the tool is positioned squarelytothe tangential plane at the point of the surface of object 19 into which it is desired to drivea stud. In this position it will be noted that the shield structureof this invention engagesa surface of the pipe, or column into which the stud is to be driven so as to not only protect the tool operator from any flying particles at the time of firing but also to position the tool at adesirable firing angle at which danger of a glancing shot is substantially eliminated. With the tool thus positioned and fully compressed against the target surface, it may be fired in safety.

In the embodiment of Figures-3 and 4 thereis shown a form of-the device of this invention having-an adjustable notch angle which permits a single shield structure to be used in' c onnection with a rnaximum range of diameters of cylindrical surfaces includingsharply curved surfaces as Well-as gently -curv ed-surf aces. 'As" in-the previous embodiment there is arear safety plate 6 carried on the front end of tube 3 and having an internal fiange55 about an aperture'20 for passage ofthe-barrel 2 of an explosive operated stud driving'tool. At the muzzle of the barrel 2, -there-'-is-moun-ted any suitable itwill beappreciated that other forms may be employed of any special shape complimentary or adaptable to special surface shapes encountered in work surfaces into which an explosivelydriven fastener is to be emplaced. In theembodiment shown in liigures l and 2 the notch is angularand embraces 'an incl uded angle of about 120 at the apex-,8 and an included angle of about 150 at the extremities adjacent plates 17 and 18. The difference in the inner and outer angle enables the muzzle fixture ofthis invention to accommodate a wide range of radiiofc'urvature encountered on the rounded surfaces.

In operation, the tool, loaded with a fastener and an explosive charge, is placed into position forfiring with the self-aligning shield structure of this invention in engagement with the cylindrical suzfaceof a piece of work which is to provide support or which is to be supported with the aid of a fastener driven into the surface. As illustrated in Figure 2 part of thev marginal portions of the side walls ll and 12 are pressed against a piece of work taking-the form of a circular cylindrical tube {19 which maybe-a pipeorcolumn only a part of which is shown. After the explosive operated tool is positioned by the operator (at a desired point on the wojrk 19 with the aid of locating marks 15 and 16, which may take the form-bf indentations. l-iigure l) or of superficailly appliedfindicia marks, "thef'operator then pushes. the tool against thecylindrical surfaceof object .19 until parts of the j rnarginal portions of notchedsides 11 and 12 at form of retainer-cap 99' functioning much' like cap 9 of the previous embodiment. 'I'heside walls, however, are in this embodiment formed by a pair of movable yoke-shaped opposingsectors 21-and 22 including arcuate side walls and lateral sections made of metal such-as steel and adapted-tobecarriedattheends of their lateral sections .pivotally-by the-plate 6 at the headed pins 23 and 24 fastened in any suitable manner as by means of threads in bosses 46and 47 of plate 6. The inside of the shield structure is provided as in the preceding embodiment with a resilient heat-resistant lining 25 which is preferably'ofa somewhat heavier section attached to the reariplate 6 and slidably bearing against the interior surface=ofthesectors-21-.and 22. Sectors 21 and 22 are provided with partial front cover plates 48 and 49 respectively.

The shield is further providedwith. additional elements for securingmovement of thehsectors in unison in order that the axis of the barrel willaalwaysxlie in the plane of bi-sectionlof the dihedraleangle formed by theanterior marginaledges' of-sectors121 and.22. :For this purpose plate .6 is provided with a pair ofslotted extensions 26 and 27, .sector 21 is provided with apair; of perforations or apertures 28 and 29 and in like manner :sector 22 is provided .with a. pairof perforation'siiil) and 31. Extending betweeneachof the apertures in sectors 21 and 22 and one or the; other of th-eqslots ,40 and .41 in the extensions 26 and 2.7 respectively is'one of the four links 32, 33, 34 and Y35. One end of each link is .pivotally connected at a perforation while vthe other end of the link is both pivotally and slidably mounted with respect to one or the otherelongated slot of extensions 26 and 27 by means -ofa suitable pin and manually releasable fastener arrangement hereinafter described.

The embodiment of Figures 3 and 4 maybe described in greater detail astoitscomponent Sector '21, which is adapted for arcuate movement, 71neludes lateral sections 36 and 37 and front cover plate 48; and likewise sector 22 includes lateral sections 38 and 39 andfront cover plate 49. Each of the lateral sections is pierced at the convergent ends for pivotal connections with one or the-other of the pins 23 and 24 by means of which sectors 21 and 2 2 arepivotally mounted on plate 6 in articulated relationship. The anterior edges of lateral sections 36and 38 of sectors 21 and 22 respectively are adapted to i rmon o th va able v-n t he while lateral sections 37 and 39 of sectors 21 and 22 respectively are adapted to fo'rm the other opposed V-notch. The space between sections 36 and 37 is partially enclosed by plate 48 and in like manner plate 49 partially encloses the space between sections 38 and 39;

Lateral sector 36 is provided with-a perforation 28 at which pivotal connection is made with link 32 at the other end of which pivotal connection is made slidably with a slot 40 in extension 26 by means of pivot screw 44. Lateral sector 38 is formed with perforation 30 at which pivotal connection is made with link 34 which in turn is connected pivotally in slidable relationship with slot 40 of the extension 26 also by means of screw 44. In like manner at perforations 29 and 31 lateral sectio'ns 37 and 39 respectively are pivotally connected with links 33 and 35 respectively which links in turn are pivotally connected slidably in slot 41 of the extension 27 by means. of screw 45. Extensions 26 and 27 with the elongated slots 40 and 41 respectively are disposed on plate 6 in perpendicular relationship with the plate 6, adjacent the lateral sectors 36, 37, 38 and 39 so that the slots 40 and 41 extend in parallel relationship to the axis of the tool barrel and the shield tube or sleeve 3 the latter of which is mounted coaxially with the tool barrel. This arrangement of parts permits the sectors 21 and 22 to move arcuately in desired unison which movement presents the axis of the tool barrel always squarely to the work surface at any of the angles of the V-no'tch obtainable with this embodiment. Sectors 21 and 22 can be fixed at the will of the tool operator at any setting of the V- notched angle desired by means of a T-head pivot screw and knurled or wing nut arrangement such as pivot screw 44 and knurled head clamp nut 42 in slot 40 for connection with links 32 and 34 and such as pivo't screw 45 and knurled head clamp nut 43 passing through slot 41 for connection with links 33 and 35. It is evident that the pivot screws 44 and 45 may be modified to serve merely to pivotally carry the end of the links in slidable relationship with respect to the slots 40 and 41 and that the pivot pins 23 and 24 instead may be provided with a clamping arrangement to hold the desired angular setting of the notches.

In this embodiment the resilient liner 25 may advantageously take the form shown in Figure 3 which includes forwardly extending side wall sections extending from the section of the pad 25 attached to plate 6 only partially to the edge section of and along the interior of sectors 21 and 22. This skirt portion of resilient pad 25 acts as a seal between sectors 21 and 22 and the plate 6, thereby minimizing flash which would be a source of considerable discomfort to the tool o'perator.

In operation of the embodiment of Figures 3 and 4, the clamping nuts 42 and 43 are first loosened to permit adjustment of the V-notch angle to a desired value suitable to an object such as 50 after which the nuts are tightened to hold this angle as in the preceding embodiment. Thereafter, as in the previous embodiments, it is merely necessary to press the shield structure of this invention and the loaded explosive operated tool associated therewith against the curvilinear surface of object 50 into which explosive driven studs are to be forceably em placed. This action, as in the previous embo'diments, allows the housing 1 to move forwardly with respect to the shield structure and barrel to further compress barrel spring 4 while the cap 99, attached with screw threaded adjustability on the muzzle of barrel 2, is positioned to abut with the surface of the object as in the previous embodiments described in connection with the tool of the aforementioned Serial No. 355,034.

Since many other embodiments of this invention may occur to those skilled in the art, it is to be understood the foregoing is intended by way of illustration of an embodiment now believed to be preferred and not as a limitation of the scope of the present invention except as set forth in the appended claims. For example, it will be understood that the rear plate 6 of the shield may itself be folded to provide the dihedral angle which constitutes the V-notch' set forth hereinbefore.

What we claim is:

1. A self-aligning shield structure for an explosively actuated stud driving to'ol comprising a plate apertured for passage of a tool barrel squarely therethrough and provided at the marginal portion thereof with forwardly extending side walls forming a gas expansion and missile confining chamber, said side walls having an edge profile including a pair of oppositely disposed V-notches adapted to position the plate in parallel with and said barrel perpendicular to the tangential plane passing through a point on a cylindrical surface at which a stud is to be driven into the surface by said tool, said side walls having a pair of partial front protective cover plates disposed remotely from and about the opening between the apexes of the V-notches.

2. A self aligning shield structure for an explosively actuated stud driving tool comprising a rectangular rear plate apertured for passage of a tool barrel squarely therethrough and provided at the marginal portion thereof with forwardly extending side walls forming a gas expansion and missile confining chamber open at the front, said side walls including an oppo'sitely disposed pair of walls notched at substantially identical included angles whereby the axis of the barrel of said tool is presented substantially squarely to the surface at the point at which a stud is to be explosively driven, wherein each of said notches consists of a relatively acute angle at the apex and a less acute angle at the extremities of the notched walls.

3. A self-aligning shield structure for an explosively actuated stud driving tool comprising a rectangular rear plate apertured for passage of a tool barrel squarely therethrough and provided at the marginal portion thereof with forwardly extending side walls said side walls being provided at the forward edge with a pair of spaced front cover plates, said rear plate, side walls and cover plates forming a gas expansion and missile confining chamber open at the front, said side walls including an oppositely disposed pair of walls spanned by said cover plates and notched at substantially identical included angles whereby the axis of the barrel of said tool is presented substantially squarely to the surface at the point at which a stud is to be explosively driven.

4. A self-aligning shield structure for an explosively actuated stud driving tool comprising a plate apertured for passage of a tool barrel squarely therethrough and provided at the marginal portion thereof with forwardly extending side walls forming a gas expansion and missile confining chamber, said side walls having an edge profile including a pair of oppositely disposed V-notches adapted to position the plate in parallel with and said barrel perpendicular to the tangential plane passing through a point on a cylindrical surface at which a stud is to be driven into the surface by said tool, said notches each consisting of a relatively acute angle at the apex and a less acute angle remotely from said apex at the extremities of the notched walls, said side walls having a pair of partial front protective cover plates disposed remotely from and about the opening between the apexes of the V-notches.

5. In a tool for explosively driving studs into cylindrical surfaces, a barrel through which the stud is ejected and a self-aligning shield structure mounted about the muzzle end of said barrel to extend outwardly around the barrel for engagement with the surface into which the stud is to be inserted, said shield comprising anterior portions forming a dihedral angle the bi-section of which includes the axis of said tool barrel, said portions being adapted to be presented in abutment with a cylindrical work surface whereby the barrel of the tool may be readily aligned in centered squared relationship to said surface, and wherein said shield on readily visible por- :7 tions of the'exterior hasfhereon indicia marks'adapting 2,594,275 the tool to positioning withgresp ect 10 each particular $660,726 spot on the cylindrical surfzce at which it is'desired to 2,700,764 drive a stud.

Rf "d'th'fi th tt 5 e erences Clte m e 1c of 11s pa en 755,363

UNITED STATES ZPATENTS 1,249,584 Wycislo Dec. -11,1917

8 Baisch 'Apr."29, 1952 'W'eingart 'Dec."1,'1953 'Catlin; Feb. 1, 1955 FOREIGN PATENTS Germagy Ian. 29, 1951 

